//居中
.juzhong{
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  top: 0;
  margin: auto;
}

//清除浮动
.clearfix{
  *zoom: 1;
  &:after{
    display: block;
    content: '';
    clear: both;
  }
}

